82 THE AMERICAN JOURNAL OF SOCIOLOGY
the influence exerted by leaders, reformers, and their likes. It is, however, not to be confounded with the larger and more fun- damental process of division of labor. It is brilliant, but wholly inadequate, to say with Tarde, "Socialite, c'est 1'imitativite." 1
The most useful variation tends to survive, and hence Bailey's term, "the survival of the unlike." Variation is one of the most important processes in nature, for on this process are built the innumerable possibilities of the division of labor. Darwin's problem was, of course, the origin of differences. Linnaeus, if he were still to pursue his plan of an inventory of nature as a species of natural bookkeeping, would be appalled at the number of species. Instead of the very modest forty thousand species comprising the sum total of all living species as computed by Biberg, writing in 1749 in Linnaeus's Amoenitates Academicae, Riley concludes that "to say that there are ten million species of insects in the world would be, in my judgment, a moderate estimate." The differentiation process is proceeding as rapidly as at any period in time past ; in fact, the strong probability is that it is increasing more rapidly. That organism is likely to spread most rapidly which differs most widely from all its fel- lows, because the field is free of competitors and there is the least impediment to its progress. This principle has been called by Darwin the divergence of character. A new character, or a new combination of characters, in any organism may tend to give such an organism an immense advantage because of the monopoly-privileges it enjoys. Freedom and liberty is the toler- ation of differences, affording a chance for natural or acquired aptitudes. A variation is generally useful because it accom- plishes something new, something which the homogeneous mass could not do before the variation occurred. Progress is gener- ally such differential interstitial growth.
Differentiation, however, is not invariably the open sesame to success. The secret of success lies in the degree of adapta- tion, and success, it may again be repeated, must be interpreted in terms of survival. We commonly say that when certain plants are transferred northward they tend to degenerate by
1 TARDE, Les lots de limitation, p. 75.
